A stunning example of a calcite ammonite fossil of the species Asteroceras obtusum from the world-famous Jurassic Coast beach of Lyme Regis, Dorset UK.
The piece of limestone matrix measures 139 mm (5.5 inches) across and the fossil ammonite measures 50 mm (1.98 inches) across. The ammonite is well preserved and has been prepared out of the rock to reveal the whole shell. This is what is known as a "popped" ammonite, meaning that when the rock split, both the positive shell and cast in the matrix were revealed. Unusually, the body chamber of the shell split open as well in this one, revealing the amazing internal crystalline calcite structure with shimmering brown "dog tooth" calcite crystals exposed. The ribs are very finely defined, and the colour is beautiful: a mix of different yellows, browns and greys. A great example of the species and impressive in the flesh. The fossil weighs 570 grams and has a cut flat base to allow it to stand freely on its own for display. These are very sought after ammonites from this world-famous location.
Around 196 million years old (Sinemurian, Early Jurassic), this fossil would make a wonderful addition to any collection.